Yesterday's post about engine retention got me curious to find the first introduction of the engine hook
These go back farther than I thought, to the Estes Model Rocket News from June, 1964. While most call them an engine hook, here they were referred to as an Engine Holder.
The first use of an engine hook was in the first Estes kit, the Scout. That engine hook was bent out of thick wire, not the flat spring steel shown here. The short engine hook was used in the Astron Sprite, also introduced at the same time in 1964.
EDIT: Bernard Cawley corrected me in a comment: The Sprite used the standard longer, 2.75" hook so the shorter 1.75" Series III engine could slide back at ejection.
To see this issue of the Estes M.R.N.: CLICK HERE
No, Chris, the Sprite didn’t use the short hook (EH-3 above), it used the EH-2 so that the motor could slide aft as it does on the music wire hook on the Scout, to make the model tumble in recovery. The EH-2 first appeared used as we expect it to - holding an 18x70mm motor - in the K-25 Alpha. It first appeared in MRN in late 1965, well before its 1967 catalog debut. The K-25 Alpha also introduced the tri-fold shock cord mount, though it appeared in lower-numbered K kits in later versions.
ReplyDeleteHi Bernard,
DeleteYou are right! I had the Sprite kit and it had to be the long engine hook. I had a few instances where the short bend on the rear of the hook didn't catch the engine at ejection. The Scout had the longer bent end.
Thanks for the info on the tri-fold mount. When I started in 1969 there were still some kits that had the slits in the body tube to tie in the shock cord.